The MinC protein is one of three proteins in the
Min system
The Min System is a mechanism composed of three proteins MinC, MinD, and MinE used by ''E. coli'' as a means of properly localizing the septum prior to cell division. Each component participates in generating a dynamic oscillation of FtsZ pro ...
encoded by the ''minB''
operon
In genetics, an operon is a functioning unit of DNA containing a cluster of genes under the control of a single promoter. The genes are transcribed together into an mRNA strand and either translated together in the cytoplasm, or undergo spli ...
and which is required to generate pole to pole oscillations prior to
bacterial cell division as a means of specifying the midzone of the cell. This function is achieved by preventing the formation of the
divisome
The divisome is a protein complex in bacteria that is responsible for cell division, constriction of inner and outer membranes during division, and peptidoglycan (PG) synthesis at the division site. The divisome is a membrane protein complex wit ...
Z-ring around the poles.
History
When initially discovered in ''
E.coli
''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus '' Esc ...
'', MinC was believed to form a stable cap by binding with
MinD
The mind is the set of faculties responsible for all mental phenomena. Often the term is also identified with the phenomena themselves. These faculties include thought, imagination, memory, will, and sensation. They are responsible for vario ...
at the bacterial caps in a stable and static manner, thereby specifying the mid-zone of the cell by lower-concentration or lack of this complex in that region, alleviating inhibition of Z-ring formation. However, Raskin & de Boer applied live-cell imaging with
GFP fusion proteins to reveal a dynamic interaction of the Min proteins, demonstrating that MinC and MinD, with the essential help of
MinE
Mine, mines, miners or mining may refer to:
Extraction or digging
* Miner, a person engaged in mining or digging
*Mining, extraction of mineral resources from the ground through a mine
Grammar
*Mine, a first-person English possessive pronoun
...
,
actually rapidly oscillate between the two poles in a non-static manner.
MinC is found in diverse genera, including
Neisseria
''Neisseria'' is a large genus of bacteria that colonize the mucosal surfaces of many animals. Of the 11 species that colonize humans, only two are pathogens, ''N. meningitidis'' and '' N. gonorrhoeae''.
''Neisseria'' species are Gram-negativ ...
,
Bacillus
''Bacillus'' (Latin "stick") is a genus of Gram-positive, rod-shaped bacteria, a member of the phylum '' Bacillota'', with 266 named species. The term is also used to describe the shape (rod) of other so-shaped bacteria; and the plural ''Bacil ...
, and
Synechocystis
''Synechocystis'' is a genus of unicellular, freshwater cyanobacteria in the family Merismopediaceae. It includes a strain, ''Synechocystis'' sp. PCC 6803, which is a well studied model organism.
Like all cyanobacteria, ''Synechocystis ...
, but is absent in an equally wide assortment of genera (e.g.
Caulobacter,
Mycobacterium
''Mycobacterium'' is a genus of over 190 species in the phylum Actinomycetota, assigned its own family, Mycobacteriaceae. This genus includes pathogens known to cause serious diseases in mammals, including tuberculosis (''M. tuberculosis'') and l ...
). Many bacteria that lack MinC carry alternative proteins that can position their Z-ring.
Function
MinC is known to dimerize
and functions as an
FtsZ
FtsZ is a protein encoded by the ''ftsZ'' gene that assembles into a ring at the future site of bacterial cell division (also called the Z ring). FtsZ is a prokaryotic homologue of the eukaryotic protein tubulin. The initials FtsZ mean "Filamen ...
protein inhibitor, antagonizing its structure assembly when in a high enough concentration. The protein has the ability to disassemble the
ZapA, ZapB and ZipA proteins which preferentially bind to the FtsZ scaffold protein and which are needed to initiate cell division.
Concentrations of MinC are lowest at the mid-zone of bacterial cells, thereby permitting septum formation and scaffold assembly at the cellular mid-zone since the Min System proteins (MinCDE) are lowest in concentration in this region, alleviating the physical inhibition on the proteins required to initiate division.
References
{{Reflist
Bacterial proteins